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Teens who smoked marijuana at least four times a week and used marijuana throughout their life saw their IQ drop an average of 8 points, according to a new study.
By Tia Ghose, LiveScience
Teens who smoke marijuana see their IQs drop as adults, and deficits persist even after quitting, according to a new study.
"The findings are consistent with speculation that cannabis use in adolescence, when the brain is undergoing critical development, may have neurotoxic effects," study researcher Madeline Meier of Duke University said in a statement.
The study followed 1,037 New Zealand children for 25 years. Subjects took IQ tests at age 13, before any of them had smoked marijuana, and again at age 38. Throughout the study, participants also answered several surveys about their drug use.
Roughly 5 percent of the participants started using marijuana as teenagers. Those who smoked marijuana at least four times a week and used marijuana throughout their life saw their IQ drop an average of 8 points, the equivalent of going from an A to a B student. The drop was not explained by other drug use, years of education, schizophrenia or using marijuana in the day before the test.
People who eventually quit smoking pot still had lower IQs than they did at the start of the study.
Interestingly, people who picked up the habit as adults had no IQ drop, suggesting that marijuana may not be as harmful to the mature brain.
The findings are the first to associate intelligence declines with marijuana use. Past work linked low IQ and marijuana, but couldn't rule out the possibility that people who choose to smoke pot are inherently less smart than abstainers.
It's not clear why pot is bad for teen brains.
One possibility is that teenagers are more vulnerable to marijuana's effects on brain chemistry, said Susan Tapert, a neuropsychologist at the University of California, San Diego, who was not involved in the study.
During adolescence, neural connections are pruned in the hippocampus and the prefrontal cortex, critical regions for learning, memory and planning, Tapert said.
Those regions may also soak up the active ingredient in marijuana."A lot of the areas that are still developing during adolescent years happen to be the areas with high cannabis receptor density," Tapert told LiveScience.
But those who consistently smoke marijuana may simply make less intellectually stimulating choices at critical points in life.
"What people tend to do when they're under the influence is different than they would otherwise," Tapert said.
For instance, pot users may be less inclined to attend classes or do other activities that give the brain a workout. Getting off track early on can also limit future opportunities and thereby reduce IQ, she said.
Related: 10 Ways to Keep Your Mind Sharp
"Teens need to view cannabis as not an entirely benign compound, but as something that can impair your judgment and might not be great for your brain," Tapert said.
The study is detailed Aug. 27 in the journal Proceedings of the National Academy of Sciences.
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Years ago I stopped listening to the statistical group that live in our world. Today red wine is bad, tomorrows study proves red wine is good, caffeine is bad..caffeine is good. Sometimes I think these stats people crave popularity, crave notoriety and create studies that are systemically flawed. It is not science. If you read the PDF of the study you will find things that would never happen in the world of science such as a lack of validation of a controlled test. "A second limitation is that we obtained information on past year cannabis dependence and self-reported frequency of cannabis use with no external validation of use"
In the pot study there is an anomaly in some of their subsets and they never explain them. One is in arithmetic. If their hypothesis were valid, the never used group would never equal the 1 diagnosis group. How do they explain 2 diagnosis at zero? They don't explain it and there are other subtests with comparable results.
Arithmetic subtest
Never used, never diagnosed: -0.05
Used, never diagnosed: −0.07
1 diagnosis: −0.05
2 diagnoses: 0.00
3+ diagnoses: 0.06
This paragraph in the study is very telling because they admit there may be unknown variables
that were at work. Is there a cultural aspect at work? Not every set of diagnosis groups had the loss of IQ that is rampant in the news.
The study’s results must be interpreted in the context of its limitations. First, although we were able to rule out a set of plausible alternative explanations for the association between persistent cannabis use and neuropsychological functioning, such as premorbid neuropsychological deficit and hard-drug and alcohol dependence among persistent cannabis users, our data cannot definitively attest to whether this association is causal. For example, there may be some unknown “third” variable that could account for the findings. The data also cannot reveal the mechanism underlying the association between persistent can-
nabis dependence and neuropsychological decline."
Trying to put out studies that have unknown variables is not scientific and IMHO not a valid study. For instance the recent study about soda and adolescent violence.
What are we to think about these studies? Yesterday I was reading a study that pointed out that children that drink soft drinks are more prone to violence. Are we to think it is the soda or is it a cultural event? Is it all about getting headlines?
"59 percent of those drinking 14 or more cans a week had been violent toward peers, compared with 35 percent of those drinking one can or less. Teens who drank lots of soda were also more likely to be aggressive toward a sibling -- 45 percent compared with 25 percent among teens who drank little soda."
I have no doubt that using any drug be it alcohol, pot, Ritalin, etc. will have some negative effects. My questions are things such as:
Should we be placing people in jail for using drugs
Is it the governments role in our life to tell people how to live (drinking soda, trans-fats, etc)
How invasive should we allow laws that are used to persuade people to increase their IQ
Should alcohol be made illegal
I've spent over a decade enjoying this plant; as such, I've known many, many people who do also. In that time, I've noticed that the 'dumb-stoner' stereotype is not a myth unfortunately; however, I don't think it's a matter of neuro-chemical influence. The stoners I've known who do nothing but smoke Indica (couch-weed) and watch cartoon network or play xbox and ps3 all day, have shown a significant decline in their ability to think. Those, like myself, who smoke Sativas or Sativa-dominant hybrids and spend that 'high-time' learning, creating, working, or bettering themselves in some way are some of the sharpest minds I've encountered. Let's not overlook the 'what' these kids do while high, and certainly not overlook the mental capacity of kids who don't use cannabis but spend their free time absorbing stupid entertainment, I would bet anything the non-smoking toon watchers are just as dumb.
Just curious...
Those opposed to marijuana: Practice organized religion, Spiritual, or Atheist?
Pro marijuana: Practice organized religion, Spiritual, or Atheist?
Me <----- Pro Marijuana, Atheist.....I belong to The Church of the Flying Spaghetti Monster.
It should be noted that just getting older lowers your I.Q. I was told this by.... drum roll... someone who was testing me for placements in higher grades at a young age in school because I was far ahead of the curve in reading and science, from spending time reading encyclopedias as a kid.
I.Q. doesn't say how smart you are. It's your ability to reason and to a lesser degree the eagerness with which your mind accepts data and translates it to thought.
As you get older, for most people, the cells, and thus the electrical current responsible for these abilities in your brain, aren't as prevelant as they once were.
Also, there have been many studies about the memory and pot. All contradict each other miserably, except, there can be no doubt that being under the influence of pot lessens the brain's ability to create new short term memories, and in theory if smoked daily, would eventually interefere with long term memory. This is simply because the brain must first create it as a short term memory, and even these are prioritized unknowingly, before it can be put into deep storage for later recall as a long term memory.
I'll believe people looking for Mensa members over some study that was most likley funded by Big Tobacco or Liquor. I am not too sure Duke University foots the bill in Pot studies, but those Big's will do everything they can to fund negativity in writing against their biggest competitor. Her name is out there and on everyone's lips (pun intended) and they want to smear it.
Never seen that before? C'mon...
My husband and I have smoked pot for over 20 years. Stopped each time I was pregnant and nursing my children, who turned into 3 healthy straight A students. My husband and I have been together for over 20 years as well, happily married. I am a college graduate who graduated with honors while smopking pot, I have taught Sunday school at my church, was employed as a director in a local school, and now run a successful business. My husband and I don't drink alcohol - just doesn't taste good to us. No one would have any idea that we are daily pot smokers. These studies are biased and ridiculous! I am living proof that smoking pot does not ruin your life. I never did any other drugs and it never got me into any trouble. People who are addicted to pot are addictive people with addictive personalities. If it wasn't pot than it would be food, alcohol, or some other addiction.
According to some of these clowns here you would have been able to do something useful with your life like maybe discover the secrets to time travel if you did not fry your brain on this most dangerous threat to society. lol
Trying to have a reasonable discussion with many of these people is like trying to explain electron theory to a chimpanzee. It's their way or the highway. They only consider studies and reports that are biased to what they want to believe. A hand full of government funded and or approved negative studies intended to reveal only the negative effects do not stand up against the multitude of international unbiased scientific research simply studying the substance and letting the results of the research speak for itself without putting a spin on it.
People believe what they want to believe.
Did you major in writing?
Where you high when you wrote that?
Your liberal President says you did not build that business
I hope you know i am kidding . Good for you , but you can't be too smart you risked everything for some dope .
Ditto that as the above post proves.
This whole argument reminds me of being a child watching National Geographic and not wanting the hungry tiger to devour a poor defenseless zebra. Our only weapon is education and for the uneducated they get eaten like the defenseless zebra in the wrong place at the wrong time. I am intrigued if this problem is solely socio-economic or are the privileged portion of society also struggling with this. Seems like population control or another way to keep the sheep in their proper areas.
Just look what pot use did to President Obama,Michael Phelps,Ted Turner,Michael Bloomberg,Montel Williams,Stephen King,Arnold Schwarzenegger,Steve Jobs,Carl Sagan and too many others to list! Can you just imagine how smart they could of been if the hadnt smoked pot? LMAO! This is just more scare tactics from our essteemed government.
Really? You needed a study to figure that out?? Ever heard of the expression "smoked themselves stupid"? Go hang around a bunch of stoners and it will be quite obvious. I'm also betting the its more than 8 points.
As a teenager I was tall worked in the fields during the summer had a good build so during high school I was designated driver to several friends, we were not into MJ only Oympia beer which I could purchase through most taverns in Moscow Idaho (Red Brick Inn) to go, all of those (kids) are gone now, I am 80 and going strong. I wonder what would have happened if they had used MJ instead of.
Wow, what a startling revelation! Regular pot smoking as a teen affects their IQ.
Now, for all you pot smokers who say "I smoked pretty regularly in high school and it didn't affect my IQ".....really? How would you know? Maybe you would be smarter?! Also, the study doesn't say EVERYONE is affected, it's just a tendency based on this study.
I'd like to discuss the article, but I forgot what it was about
HA HA, HA...ha..........ha. That...was...so...funn....ZZZzzzzz.
Interesting. When I was in post high school studies, my GPA was 3.90 with no marijuana use. Then, when I would partake of the evil weed, the GPA went up to 4.00. And when I did the std. I.Q. test, my I.Q. was 143. Which means it was 151 before use of pot? Oh, wait a minute- I was no longer a teen when I put up those numbers in tech school and had the I.Q. test. So, that does not count. Or, I would be considered an anomaly and my results would not be considered...
It's hard for pot smokers to accept the inherent damage being done to their bodies and minds; just as it is for addicted cigarette smokers and excessive alcohol drinkers.
There are laws against suicide but no laws to prevent suicide by attrition.
The reason why?
It is a form of population control.
It's a fact that pot and cigarette smokers and abusive alcohol drinkers will die sooner.
They should be free to do so, as many here argue; and thus by dying sooner they will contribute to not over-populating the planet.
{ ◎⃝ᴥ◎⃝ }
Good post Coral , that explains the Dirty Rats profile.
Everyone should read the rest of it. Seems he is proud of himself . Why i do not know?
Here, I'll make it easy for you to check it out right here on this thread. Yes, I am proud of who I am and I could really give a @!$%# what you or anyone else thinks of me because you, and any one else for that matter, don't mean squat to me. I have a loving family and that is all that really matters to me.
Take it or leave, I could really care less (I all ready know you will leave it).
@Coral Atlas:
Hey, Coral..........does that include recreational pot users like me? Ones that only smoke once or twice a year?
If so, please direct me to the research that proves someone like me (a mountaineer in excellent shape, that doesn't drink or do anything else) is going to die earlier because I smoke a joint once a year.
I'll be waiting.
well Rat, I am sorry you're disabled. Oh and i do like your avatar. If being bitter as you seem to be works for you, so be it.
You are not the only one that has been though tough times or is going through tough times.
Smoke'em if you got em.
Hope that crutch(maryjane) works for you.
Good luck , Oh and GOD Bless.
retired:
Thank you for the sentiment. Yeah, I thought that was a pretty cool avatar which I swiped from the internet (Google images).
Why would you think I'm bitter? You don't think my response was deserving considering you said:
That's a personal attack in my book.
Well, no @!$%# Sherlock. The way I look at it, I have been very lucky to have the life I've had and I don't take it for granted. If I were to die tomorrow I would be happy to go with no regrets (except missing the vote on weed legalization coming up this election). Just so you know I volunteer at a children's hospital so you don't need to tell me I'm the only one going through tough times. I would gladly trade places with those kids that are very sick or terminally ill. Maybe that might shed some light on the kind of person that I am.
I would if I could but I can't so I won't.
What you consider a crutch I consider a recreation. I don't need weed to cope as you would suggest. I really don't like alcohol and I certainly wouldn't want to be doing any hard drugs, especially with my poor health. My doctor doesn't lecture me at all about weed; he's happy that I gave up that nasty habit of nicotine. And before you jump to any conclusions, just so you know, my disease is genetic. Enough about me.
LOL You crack me up. You just had to throw in the "GOD Bless", huh? Well, whatever you say. God doesn't exist. If he does, I have many issues to pick with him because, with his all powerful self, he is a @!$%#ing @!$%# to let so much misery exist in the world when he has the power to change that. Don't give me that line of crap, "he works in mysterious ways". That's just a cop out explanation.
BTW- Since you are showing me some kind of civility here, I would like to thank you for your service to our country.
Peace.
Peace to you to rat.
You might like this...
http://www.markfiore.com/what_if_0
Good research costs money. That is why this is not a good scientific paper. I see young adults smoking cigarettes and I wonder why they are not smoking weed. Never combine them though. The carcinogenic property in the cigarette are enhanced by the inhaled vapors of the weed. By itself weed is far safer than alcohol and probably prevents more cancers than it causes if any.